The California Supreme Court grappled Wednesday with whether to hold amusement parks liable for injuries that occur during a ride's normal operation. Meeting for oral argument, the state high court considered a lawsuit filed by a woman who broke her wrist while riding a bumper car at the Great America amusement park in Northern California. She claimed the park had operated the ride negligently and should compensate her for the injury. Cedar Fair L.P., the company that owns the park, countered that riders assume responsibility for themselves when they knowingly hop on an attraction with inherent risks.